The opioid crisis that is ravaging urban and suburban communities across the US claimed an unprecedented 59,000 lives last year, according to preliminary data gathered by the New York Times. If accurate, that’s equivalent to a roughly 19% increase over the approximately 52,000 overdose deaths recorded in 2015, the NYT reported last year.

Overdoses, made increasingly common by the introduction of fentanyl and other powerful synthetic opioids into the heroin supply, are now the leading cause of death for Americans under 50. And all evidence suggests the problem has continued to worsen in 2017. One coroner in Western Pennsylvania told a local newspaper that his office is literally running out of room to store the bodies, and that it was recently forced to buy a larger freezer.

The initial data points to large increases in these types of deaths in states along the East Coast, particularly Maryland, Florida, Pennsylvania and Maine. In Ohio, which filed a lawsuit last week accusing five drug companies of abetting the opioid epidemic, the Times estimated that overdose deaths increased by more than 25 percent in 2016.

In some Ohio counties, deaths from heroin have virtually disappeared. Instead, the primary culprit is fentanyl or one of its many analogues.In Montgomery County, home to Dayton, of the 100 drug overdose deaths recorded in January and February, only three people tested positive for heroin; 97 tested positive for fentanyl or another analogue.

In some states in the western half of the US, data suggest deaths may have leveled off for the time being – or even begun to decline. Experts believe that the heroin supply west of the Mississippi River, traditionally dominated by a variant of the drug known as black tar which is smuggled over the border from Mexico, isn't as easily adulterated with lethal analogues as the powder that's common on the East Coast.

First responders are finding that, with fentanyl, carfentanil and the other analogues, overdoses can be so severe that multiple shots of naloxone – the anti-overdose medication that often goes by the brand name Narcan – are needed to revive people. One EMT in Warren County, Ohio told the Times that sometimes as many as 14 doses of Narcan are needed to revive a patient.

“It’s like a squirt gun in a house fire,” the EMT said.

But, as Robert Anderson, chief of the Mortality Statistics Branch of the National Center for Health Statistics at the CDC explains, toxicology results, which are necessary to assign a cause of death, can take three to six months or longer.

“It’s frustrating, because we really do want to track this stuff,” he said.

While the process in each state varies slightly, death certificates are usually first filled out by a coroner, medical examiner or attending physician. These death certificates are then collected by state health departments and sent to the N.C.H.S., which assigns what’s called an ICD-10 code to each death. This code specifies the underlying cause of death, and it’s what determines whether a death is classified as a drug overdose, the NYT reported.

We can say with confidence that drug deaths rose a great deal in 2016, but it is hard to say precisely how many died or in which places drug deaths rose most steeply. Because of the delay associated with toxicology reports and inconsistencies in the reported data, our estimate could vary from the true number by several thousand.